Introduction: Advanced intraocular retinoblastoma can be cured by enucleation, but spread of retinoblastoma cells beyond natural limits of the eye may lead to metastatic disease which is related to a high mortality. Adjuvant therapy after enucleation has been shown to prevent metastasis in children with risk factors for extraocular retinoblastoma. However, histological criteria and adjuvant treatment regimens vary and there is no unifying consensus on the optimal choice of treatment. Method: Data on guidelines for adjuvant treatment in European retinoblastoma referral centres were collected in an online survey among all members of the European Retinoblastoma group (EURbG) network. Extended information were gathered via personal Email communication. Results: Data were collected from 26 centres in 17 countries. Guidelines for adjuvant treatment were in place at 92.3% of retinoblastoma centres. There was a consensus on indication for and intensity of adjuvant treatment among more than 80% of all centres. The majority of centres use no adjuvant treatment for isolated focal choroidal invasion or prelaminar optic nerve invasion. Patients with massive choroidal invasion or postlaminar optic nerve invasion receive adjuvant chemotherapy, while microscopic invasion of the resection margin of the optic nerve or extension through the sclera are treated with combined chemo- and radiotherapy. Conclusion: Indications and adjuvant treatment regimens in European retinoblastoma referral centres are similar but not uniform. Further biomarkers in addition to histopathological risk factors could improve treatment stratification. The high consensus in European centres is an excellent foundation for a common European study with prospective validation of new biomarkers.

Background: Leukemia in children has a good prognosis with an overall cure rate of 85% in pediatric patients with acute lymphoblastic leukemia and 50-60% in pediatric patients with acute myeloid leukemia. Nevertheless in patients with refractory or relapsed leukemia the prognosis is limited and can only be cured by a salvage chemotherapy, in most cases followed by an allogeneic hematopoietic stem cell transplantation. Methods: In this retrospective case cohort ananlysis we investigated the outcome of eight patients with relapsed or refractory acute myeloid (n=2), lymphoblastic (n=4), biphenotypic (n=1) leukemia or T-lymphoblastic lymphoma (n=1) who failed to respond to standard salvage regimens. They received a salvage therapy with melphalan and cytarabine at our institution between 2015 and 2019. Results: After salvage chemotherapy with melphalan and cytarabine 63% of the patients achieved a remission of the disease and qualified for subsequent allogeneic hematopoietic stem cell transplantation. The one year overall survival rate was 50%, the three year overall survival rate was 29%. 25% of patients experienced a temporary period of fever and SIRS. Conclusions: The reported results of our case cohort analysis indicate that a salvage therapy with melphalan and cytarabine in relapsed or refractory leukemia could represent a curative approach with the possibility of achieving remission and subsequent allogeneic hematopoietic stem cell transplantation. Future multicentre studies are needed to verify the here presented results.